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  <title>Description of pca_randomvector</title>
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<h1>pca_randomvector
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<h2><a name="_name"></a>PURPOSE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="box"><strong>Generate random vectors in PCA subspace.</strong></div>

<h2><a name="_synopsis"></a>SYNOPSIS <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="box"><strong>function Xr = pca_randomvector( U, mu, variances, k, n, hypershpere, show ) </strong></div>

<h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="fragment"><pre class="comment"> Generate random vectors in PCA subspace.

 Used to generate random vectors from the subspace spanned by the first k
 principal components.  The points generated come from the gaussian
 distribution from within the subspace.

 Can optionally generate points on the subspace that are also on a
 hypershpere centered on the origin.  This may be useful if the original
 data points were all from a hypershpere -- for example they were
 normalized via imnormalize.  Set the optional hypershpere flag to
 1 to generate points only on the hypersphere.

 INPUTS
   U           - [returned by pca] -- see pca
   mu          - [returned by pca] -- see pca
   variances   - [returned by pca] -- see pca
   k           - number of principal coordinates to use
   n           - number of x to generate
   hypershpere - [optional] generate points on hypersphere (see above)
   show        - [optional] figure to use for display (no display if == 0)

 OUTPUTS
   Xr          - resulting randomly generated vectors

 DATESTAMP
   29-Nov-2005  2:00pm

 See also <a href="pca.html" class="code" title="function [ U, mu, variances ] = pca( X )">PCA</a></pre></div>

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<h2><a name="_cross"></a>CROSS-REFERENCE INFORMATION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
This function calls:
<ul style="list-style-image:url(../matlabicon.gif)">
<li><a href="../images/imnormalize.html" class="code" title="function X = imnormalize( X, flag )">imnormalize</a>	Various ways to normalize a (multidimensional) image.</li><li><a href="../images/montage2.html" class="code" title="function varargout = montage2( IS, showlines, extrainfo, clim, mm, nn, labels )">montage2</a>	[3D] Used to display a stack of T images.</li><li><a href="../matlab/feval_arrays.html" class="code" title="function B = feval_arrays( A, fhandle, varargin )">feval_arrays</a>	Used to apply the same operation to a stack of array elements.</li></ul>
This function is called by:
<ul style="list-style-image:url(../matlabicon.gif)">
</ul>
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